1. Field of Invention
This invention relates to the building and construction arts, specifically to devices which are particularly effective in applying and finishing viscous materials along at least one adjoining surface, which are easy to use and efficient in producing a uniform, clearly defined continuous junction of the applied surface and the adjoining surface, while simultaneously all of the surfaces are effected substantially free of any excess of the material being applied.
2. Description of Prior Art
Heretofore, tools or other devices and methods for applying and finishing drywall joint compounds, spackle, plaster, cement, concrete, caulking, thinset, tile grout, other grouts, adhesives, resins, mastics, or other viscous materials, along at least one adjoining surface, have not been easy to use or efficient in effectively producing a uniform, clearly defined junction of the applied surface and the adjoining surface (here after to be referred to as adjoining surface), while simultaneously all of the surfaces are effected substantially free of any excess viscous material. Some of the commonly used tools for this process are a drywall taping knife or finishing knife, a float or finishing trowel for cement, a float or finishing trowel for plaster, a putty knife, etc., which have a semirigid, flat blade with rigid side edges at about 90 degrees to a straight forward working edge. For Example, during original construction and repair work, interior and exterior corners are frequently encountered where the surface to be worked upon more or less butts up against an adjoining surface. Some of the frequently encountered corners are where one wall adjoins either the ceiling, floor or another wall; where a wall meets a door casing, window frame, crown and base moulding, coving or wainscoating; where a window sill and/or jam meets a window frame; where a concrete slab meets a wall, or any other instance where a corner exists.
A two step operation for each application of material has been necessitated, by the fact that in the first step, the prior art devices currently in use fail to compensate for corner surface irregularities, thereby, depositing excess material upon the adjoining surface. This results in additional time and labor being spent to remove the excess material in the second step of the operation. In addition the second step exacerbates the possibility of physical disorders and injuries resulting from prolonged repetitive motions, e.g. carpal tunnel syndrome, grip loss, joint irritation and inflammation, etc.
The manner of using some of the commonly used prior art tools, to apply and smooth out viscous materials along an adjoining surface, is as follows: in the first step of the operation, while drawing one of the currently used tools along an inside corner, the tool is positioned with the working face of the tool blade basically at an acute angle to the work surface to be coated (here after to be referred to as work surface); the viscous material is sandwiched between the working face of the tool blade and the work surface; the forward working edge is more or less against or skimming over the work surface to which the material is being applied and is more or less at a right angle to the adjoining surface; one of the side edges of the tool is continuously pressed against and guided by the adjoining surface. The rigid side edges of the prior art tools do not compensate for irregularities of the adjoining guide surface and any inconsistencies of the angle of the corner being worked upon. In addition, they do not accommodate corners which deviate significantly from being more or less at right angles. The rigidity of the currently used tools results in the viscous material oozing between the side edge of the tool blade onto the adjoining surface. Furthermore, it is not feasible for a craftsman to continuously hold the prior art tools in a position to clean the adjoining surface of material being applied, while simultaneously applying and finishing the material along the same adjoining surface.
In the first step of the operation of applying and finishing, one of the forward corners of the tool blade is commonly pressed against the adjoining surface in order to extend the plane of the applied surface to the adjoining surface and clearly define the corner of the two surfaces. Thus, to insure continuous contact of the forward corner of the tool blade and the adjoining surface, the blade side edge is slightly pivoted away from the adjoining surface. The slight acute angle of the tool side edge and the adjoining surface allows the material being applied to flow between the tool side edge and the adjoining surface. This results in excess material being deposited onto both surfaces, mainly the adjoining surface. This excess material then must be removed in the second step of the operation.
The area of contact, between the forward corner of the tool blade and the adjoining surface which serves as a guide, is very small and does not span most irregularities of the adjoining guide surface. The blade, being rigid, transfers the shock, from the side edge traveling along the adjoining guide surface, to the forward working edge. The blade is very sensitive to the shape and texture of the adjoining guide surface. As the tool is pulled along the work surface and one of the forward corners of the blade rides along the adjoining surface, it follows the shape and texture of the adjoining surface. If the adjoining guide surface is not smooth, the rapid movement of the blade following the adjoining surface causes the blade to chatter, effecting irregularities in the applied surface, commonly referred to as chatter marks. In addition, the small point of contact between the forward corner of the tool blade and the adjoining guide surface tends to scrape a groove in the adjoining surface, with particles of material being scraped off and contaminating the material being applied. Therefore, the prior art tools require great skill to produce a smooth applied surface.
In the second step of this operation, employing the same tools as above or other devices, the undesirable excess material, which has oozed between the tool side edge and the adjoining surface, must be carefully scraped from the surfaces to eliminate protrusions from both surfaces. This is usually done after the material is fully dry or set. This procedure requires extreme care to avoid damaging the surfaces with the tool blade. For example, the adjoining surface can be scratched with the tool blade; cavities can occur where protrusions have been scraped away from the surfaces; the tool blade can cut into the applied surface while scraping excess material from the adjoining surface; the dried material, which had been urged into the void between the two adjoining surfaces, can be knocked out or cracked, etc.
Multiple applications of material are usually required to effect the desired results. For example, in residential and commercial construction sheets of gypsum wallboard, commonly known as drywall, that are usually 4 feet by 8 feet and from 0.5 inch to 0.75 inch in thickness, are fastened to vertical studs and horizontal joists by nails or screws. Due to irregularities in the framing, the adjoining surface, and/or the employed drywall edge there is usually a gap between the new wallboard surface and the adjoining surface. The gap is usually bridged with a reinforcing material, e.g. paper or fiberglass joint tape. The edge of the tape butts up to and conforms to the adjoining surface, thereby, extending the plane of the new drywall surface to the adjoining surface. The tape provides a bridging strength to the joint compound and conceals the gap at the corner. The craftsman first applies a bed coat of joint compound, in a relatively stiff aqueous slurry form, then lays the joint tape in the bed coat while it is still wet. Then, while drawing a taping knife or other device along the corner, as described above, the tape is pressed against the drywall work surface. This procedure squeezes out the excess compound and air pockets to ensure good penetration of the compound and adherance of the joint tape to the work surface. The craftsman removes the excess material after the compound is allowed to dry, usually for about one day. The craftsman then applies an additional coat of joint compound over the reinforcing tape. During the drying process the compound shrinks as the water evaporates from the compound, thereby, causing irregularities, such as concavities, in the applied surface. Therefore, three to four applications of joint compound are required to achieve a smooth surface. Furthermore, the damage to the surfaces incurred by the removal of the excess material, which has oozed between the side edge of the tool blade and the adjoining surface, necessitates the need for additional applications of material to fill in the voids.
In order to achieve the desired results, it is also common to apply one or more rough coats and finish coats of other viscous materials, e.g. spackle, plaster, and the like, due to voids, shrinkage, and/or to build up and shape the applied surface. Each additional application of material involves additional problems. If the adjoining surfaces are not scraped completely clean of excess material to provide smooth consistent guide surfaces for the tool blade to follow at the small rigid point of tool to surface contact, the tool will follow the uneven, irregular shape and texture of the surfaces, thereby, causing inconsistencies, e.g. chatter marks in the surface of the material applied. In order to fill in the valleys of the chatter marks, the craftsman must draw the tool in the opposite direction of the previous application. This is done by placing the forward working edge of the tool blade in and parallel to the inside corner, carefully tight against the adjoining surface, and then pulling it across the surface away from the inside corner. The attitude of the forward working edge of the tool blade is more or less at a right angle to the chatter marks, thereby, enabling the forward edge to span the indentations of the chatter marks. Otherwise, the tool would follow the shape and texture of the chatter marks in the previously applied surface. However, when running the tool blade in this direction the tool blade is not guided by firm guide surfaces, rather it skims along the soft material being applied. The craftsman attempts to apply a uniform surface in multiple and usually short overlapping passes. An attempt is made for each pass to effect a surface in the same plane of the previous pass, by floating the tool blade on the material being applied. This is a time consuming procedure that requires great skill to produce good, uniform results. Furthermore, the blade effects ridges in the applied surface, when the forward corners of the tool blade ride on the surface of the material being worked. These ridges, in the second step of the operation, are then scraped and/or sanded off of the surface when dry or set.
The scraping and sanding required in the second step of the operation produces particles of dried material and dust. In order to achieve good results, these particles and the dust must be removed from both surfaces before each additional application of material. The dust prevents the material from bonding to the work surface. If the particles of dried material, from the second step, are mixed in with the material being applied, the tool blade chatters as it rides on the chunks of dried material, thereby, effecting irregularities in the applied surface. Furthermore, the chunks of dried material stick to the forward working edge of the tool blade effecting grooves in the applied surface. Additional work time is required in the second step for the craftsman to fill in the chatter marks and/or grooves in the applied surface. The prior art tools, described above and other devices, are also used to clean the above described viscous materials and other materials out of bucket bottoms, drywall mud pans, etc. The same problems exist as a result of the tool blade being nonconforming, i.e. the material oozes between the side edge of the tool blade and the container, making it difficult to clean the container. Furthermore, the rigid edges of the tool blade tend to cut into and catch on the side walls of five gallon plastic buckets and other like surfaces. Plastic buckets are commonly used for mixing and holding drywall joint compound and the like. Therefore, cleanup of the aforementioned surfaces is a difficult and time consuming operation. These and other tool blades are usually made from some type of metal; for example, spring steel, which is flexible, but is susceptible to corrosion, such as rust.
In order to control the flexing and manipulate the blade of prior art tools, pressure is applied more or less continuously to various areas of the surface of the tool blade and to the handle. The desired flexing, in many situations, requires constant extension of the index finger and application of pressure by the finger, resulting in consistent, prolonged stress upon the joints in the hand and wrist area. In addition, repeated movement and rotation of the wrist joint is required, frequently resulting in carpal tunnel syndrome, grip loss, joint irritation and inflammation, and other work related physical disorders which result from prolonged repetitive motions. This has great significance as it has been estimated that prolonged repetitive motions are responsible for nearly 50% of disorders related to employment. The prior art tools require costly, tedious, and laborious reworking, for even the most proficient craftsman, to produce a high quality finished product.
Heretofore, tools or other devices and methods for forming a bead of caulking, sealants, or other viscous materials along a corner have not been easy to use or efficient in effectively producing uniform, clearly defined continuous junctions of the applied bead surface and the adjoining surfaces, while simultaneously effecting all of the surfaces substantially free of any excess of the material being applied. Some of the commonly used tools for this process are a wet sponge, one's finger, or a putty knife, which are cumbersome and relatively ineffective. For example, during original construction and/or repair work, interior and exterior inside corners are frequently encountered where there is an undesirable crack, seam, and/or irregularities at a corner. A bead of caulking is dispensed along the corner. The bead of caulking is then usually formed into a continuous uniform surface along the corner. The formed bead is intended to conceal the crack, seam, and/or irregularities of the corner. Often the formed bead is to remain unpainted or otherwise aesthetically blended with the adjoining surfaces. In most cases, the formed bead surface and the adjoining surfaces are desired to have clearly defined continuous corners, and to be free of excess viscous material. The various prior art devices used for this process do not produce the desired results easily and efficiently.